Allium Sphaerocephalon This summer-flowering allium has ramrod-straight stems that reach between 60 and 90 cm (2 - 3 ft). Each slender stem is topped by a small, oval chartreuse-green head tinged with maroon-claret at the tip. Drift it through borders en masse to provide light vertical accents, or plant it in clusters of nine, eleven or fifteen.
Where will it grow?
Like most bulbous plants alliums, or ornamental onions, do best in sunny, well-drained positions. They are perfectly hardy and will come back year after. And they are not aggressive self seeders - like some ornamental alliums.
When shall I plant it?
The ideal time for planting all alliums is September. However they can also be planted in spring, although they may not flower as well in their first year. Buy at least fifty, scatter them randomly through a sunny border and plant to a depth of three inches aiming to form a ribbon of colour. Alternatively you can pot them up in fives or sevens and plant them out in any gaps.
When will it flower?
Allium sphaerocephalon flowers at the beginning of July, much later than most purple and lavender alliums. The flowers last for weeks, before fading to bleached canvas in autumn.
What can I plant with it?
The softly swirling grass, Stipa tenuissima, makes a fine partner because it contrasts strongly in form and texture. Add a summer mixture of perennial, flat-topped achilleas including lots of the rust-orange 'Walther Funcke' and the pale-yellow 'Martina' set against one or two deep-red achilleas. 'Summer Wine' is the best, but 'Cerise Queen' also works well.
Alternatively thread it through old-fashioned roses with flowers that come in shades of pale-pink, magenta and madder. Or use it with the tall, burnished flowers of Crocosmia masoniorum. The similar Allium 'Hair' is a more-ragged lookalike and they look good together.
How do I look after it?
This plant needs to be planted and left to get on with it. It will die down every winter and reappear in spring and occasionally you may have to plant a few more bulbs.
Where can I buy it?
This widely available bulb is found in most garden centres. You can also buy it from www.crocus.co.uk, www.thompson-morgan.com and www.fothergills.co.uk